Trading game · interview prep
Market making games: how they work, and how to practise
Almost every trading firm runs one in its final rounds. You are asked to quote both sides of a price on something uncertain, the interviewer trades against you, and how you handle the next thirty seconds decides more than the number you said. This page explains the format, works through an example, and gives you places to practise.
What the game is
Each round asks you to make a two-way price on an uncertain value, then defend that quote against flow. Some traders are noise. Others know more than you do. If you quote too tight, the sharp flow lifts your mistakes immediately. If you quote too wide, you protect yourself but never trade. That tension is the point: market making interviews are rarely about a single right number. They are about balancing edge, inventory, and information in real time.
Why it matters in interviews
Firms such as Optiver, IMC, Flow Traders, and Jane Street often test the habits behind a quote, not just arithmetic. They want to hear how you anchor fair value, why you widened after a bad fill, and whether you understand adverse selection instead of memorizing jargon.
A worked example: quoting your first market
Suppose an interviewer says: make me a market on the number of countries in Africa. Here is the whole exercise, start to finish.
- Estimate fair value out loud. Say your reasoning, not just a number. Around fifty, because the continent has a lot of small states and you can name a dozen without trying.
- Set a width that matches your uncertainty. You are not confident, so quote wide: 45 bid, 58 offered. A tight market on something you barely know is the single most common candidate error, because it advertises confidence you have not earned.
- Read the trade you get. If the interviewer buys at 58 without hesitating, they think the answer is above 58. That is information, and it is bad news for you. Your fair value should move immediately.
- Requote skewed, not just wider.After being lifted, something like 52 bid, 65 offered. You have moved your centre toward the side that traded, which is what a real desk does when flow tells it something.
- Say what would change your mind.The best answers end with a condition: if you sell me another at 65 I will assume I am still too low and move again.
Nobody is grading you on knowing the answer, which is 54. They are grading whether you widen when uncertain, whether you update when a trade goes against you, and whether you can keep quoting after being wrong. That is why these games appear in final rounds: they are the closest thing to watching someone trade.
Where to practise, free and paid
- Free, right now: the classic interview questions build the expected-value reflex every quote rests on, and the 80 in 8 benchmark trains the arithmetic speed you need to price under pressure. No account required for either.
- Away from a screen: the Pit card game teaches flow reading and adverse selection with a deck of cards and three friends.
- The full simulation: the Market Maker game below quotes you against bots holding noisy private estimates of the true value, so tight quotes get picked off and wide quotes never fill. It is part of QuantPit membership.
How to practice with it
Start by learning the building blocks in the market-making question set and the broader question bank. Then use the timed tests to sharpen arithmetic and reaction speed before coming back to the game. The best way to use this page is to narrate every quote: what your fair value is, how uncertain you feel, what trade would make you move, and whether your last fill was good news or bad news. That habit is what turns a simulation into interview-ready judgment.
The game also builds transferable skills: bid-ask discipline, quick expected-value thinking, inventory awareness, and the confidence to update on order flow without panicking. Those are the same muscles you need when a recruiter pivots from a puzzle into a trading conversation and asks you to make a market on the spot.
Common questions
What is a market making game in a trading interview?
The interviewer names something uncertain and asks you to quote a price you would buy at and a price you would sell at. They then trade against you, and you requote. It tests how you price under uncertainty, how wide you go when you know little, and whether you update after a trade goes against you.
Can I play a market making game online for free?
QuantPit's free tier includes the 80 in 8 arithmetic benchmark and the classic interview questions, which build the pricing and expected-value reflexes the game rests on. The full Market Maker simulation, where bots with private information trade against your quotes, is part of membership.
How wide should I quote when I have no idea?
Wider than feels comfortable. The width should express your uncertainty, so a question you know little about deserves a wide market. Quoting tight on something you cannot estimate is the most common candidate mistake, because it invites the interviewer to trade against the side you got wrong.
What does the Market Maker game train?
It trains two-way quoting, spread sizing, skew adjustments, and reacting to informed flow without overtrading.
Which firms is this most relevant for?
It maps especially well to Optiver, IMC, Flow Traders, Jane Street, and other firms that use market-making interviews or trading games.
How should I practice with it?
Start with the market-making topic page and question bank, then play short sessions while narrating why you widened, tightened, or skewed your quotes after each trade.